Microorganisms have been harnessed for a variety of beneficial processes such as the production of foods, beverages and pharmaceuticals, and the remediation of air, soil and water.
The factors that influence these processes may include the presence and quality of food and nutrients, the presence and quantity of toxic chemicals, the degree of aeration, pH, and temperature. These factors may interact in an additive, synergistic, or antagonistic manner. In bioremediation processes, the situation is further complicated because the medium to be treated is often highly complex and variable.
Effective monitoring technologies are an important component of a successful biological process. They form the tools to build a stable and efficient biological process. Most powerful is a technology that provides information of the effects of operating environment on the microorganisms. Statistical process analyses on the data generated from such a technology can be used to solve problems and enable continual process improvement.
ATP is the keystone of metabolic activity. Most of the energy for microbial processes microorganisms is stored and transmitted via ATP. ATP is produced as microbial food is consumed and is utilized for cell maintenance and the synthesis of new cells and biochemicals.
ATP is most easily measured by the firefly luciferase assay. The reaction is as follows:

in which,
ATP=Adenosine triphosphate
AMP=Adenosine monophosphate
PPi=pyrophosphate
The chemical energy produced from the breakdown of ATP is converted into light energy. Each molecule of ATP consumed in the reaction produces one photon of light. This light output can be quantified in a luminometer.
ATP measurement has been proposed as a tool to assist in the process control of biological waste treatment systems for over 3 decades (1-3). Generally, the concept has been to substitute ATP as a more accurate estimate of the amount of viable biomass in the reactor of a biological wastewater treatment facility. This has been commonly estimated by measuring the volatile suspended solids (VSS).
However, the concepts in these references have never included measurements of dissolved ATP (d-ATP) or extracellular ATP. All analyses have been performed measuring total ATP (t-ATP), which is the combination of intracellular ATP plus extracellular ATP. Dissolved ATP analyses have been used in sanitation monitoring, but only as a measure of non-microbial ATP from food sources. Similarly, in microbial growth control, dissolved ATP has been monitored, but only in the presence of conditions that are highly lethal to microorganisms.
In addition, reagents for simple but accurate measurement of dissolved and total ATP have not been optimized for biological process monitoring. Biological remediation and production processes differ from the mainstream applications of ATP analyses—sanitation monitoring and microbial growth control—in that samples contain up to 1000 times higher levels of biomass or greater. Furthermore, biological wastewater samples contain many substances that interfere with the firefly luciferase assay for measuring ATP.
Reagent formulations containing luciferase and luciferin for assaying ATP in a sample are known in the art. For example, U.S. Pat. No. 6,004,767 of Crouch et al. discloses a bioluminescent reagent as a freeze dried powder, to be reconstituted prior to use. U.S. Pat. No. 5,558,986 of Lundin discloses such reagent formulation for use in combination with a cyclodextrin. US patent application No. 2001/0046687 of DiCesare also discloses the use of such formulation, wherein trehalose is used to enhance the emission of light intensity. Published international patent application, WO 94/11528 of Foote and Grant discloses an aqueous composition including polyols for use in a bioluminescent assay by adding a strong buffer to give a pH which is close to the optimum pH for the luciferase reaction.